Note: In a future release of apcupsd this procedure will be replaced by a daemon operation that can be performed on all types of UPS.
This section does not apply to voltage-signalling or dumb UPSes such as the older BackUPS models.
Smart UPSes internally compute the remaining runtime, and apcupsd uses the value supplied by the UPS. As the batteries age (after say two or three years), the runtime computation may no longer be accurate since the batteries no longer hold the same charge. As a consequence, in the event of a power failure, the UPS and thus apcupsd can report a runtime of 5 minutes remaining when in fact only one minute remains. This can lead to a shutdown before you might expect it, because regardless of the runtime remaining that is reported, the UPS will always correctly detect low batteries and report it, thus causing apcupsd to correctly shutdown your computer.
If you wish to have the UPS recalibrate the remaining runtime calculations, you can do so manually as the current version of apcupsd does not support this feature. To do so,
In principle, you should be able to do this with the computer powered by the UPS, but if you wish to be completely safe, you should plug your computer into the wall prior to performing the runtime calibration. In that case, you will need to artificially load the UPS with light bulbs or other means. You should supply a load of about 30 to 35% but not more than 50%. You can determine the load by looking at the output of the apcaccess status command while apcupsd is running.
You should not run the recalibration command more than once or twice per year as discharging these kinds of batteries tends to shorten their life span.
Serial-line UPSes that speak the apcsmart protocol log all of the events described in the Status Format (see apcupsd Status Logging) section of the Technical Reference. Voltage-signalling UPSes, on the other hand, have a much narrower data channel. They can only report a small handful of conditions.
The following summarizes (rather sketchily, sorry) the data you can expect to get from this obsolete hardware. All corrections and additions will be welcome.
From BackUPS Pro and SmartUPS v/s:
LINEFAIL : OnlineStatus BATTSTAT : BatteryStatus MAINS : LineVoltageState LASTEVNT : LastEventObserved
BackUPS and NetUPS Simple Signals
LINEFAIL : OnlineStatus BATTSTAT : BatteryStatus